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OctoScope’s new refrigerator-sized anechoic chamber, called the octoBox , reminds me of past projects involving RF and EMI testing. When I was at Jabil Circuit, they had a nice 100 sq ft walk-in chamber. The DUT and antennas could be placed in the chamber…

The most common failure mode I notice in cheap consumer electronics is failure of capacitors. A rough rule electrolytic capacitor life is it doubles for every ten degrees below the rated temperature. If the capacitor does not handle large AC currents…

Last June I wrote about issues of coexistence of GPS and Lightsquared’s 4G nationwide wireless broadband system . At that time I was not able to get a comment from either Lightsquared or the GPS receiver manufacturer interest group, the Coalition to Save…

A few weeks ago I checked out Ben Bova’s Able One from my library in the format of a preloaded digital audio player. The device is like a portable MP3 player dedicated to playing a single book. I found the player did not work on a NiMH cell but worked…

Lately I have come across articles about Congressional measures to improve public safety communication interoperability in the event of a disaster like the Sept 11 attacks. The narrative goes that the 9/11 Commission recommended public safety radio equipment…

This past week my local section of the IEEE hosted a talk by Tom Coughlin on consumer data storage. One thing that struck me is the sheer amount of data consumers are storing. The survey shows storage doubling every two years and starting at a larger…

The year was 1990. Some friends and I marveled at one of the first handheld transmitters in the 800MHz band. We had all used handheld transmitters at lower bands, but somehow transmitting close to 1000MHz made it “microwave” and therefore scary. In a…

A colleague asked me the other day about a circuit I did with a transistor that turned LEDs on and off. This circuit was a tiny part of the board, just a way to save energy and prevent stray light interfering with optical detectors on other parts of the…

The nagging pain in my abdomen had reached the point where I finally reached for my phone. It was time to see a doctor and put an end to whatever was causing so much pain and discomfort. What followed was a diagnosis, a cure, and some thoughts on the…

I recently selected a BJT for use in a power supply circuit. It was nothing complicated, so I used the venerable ‘3904. The transistor would have to handle 0.5A, so I needed to verify I wouldn’t need a high-power transistor. I expected the collector-to…

Until the past year, the tightest PCB trace separation I have had to use is 5 mils [0.13mm]. Typically I try to use 8 mils [0.20mm] or 10 mils [0.25mm] if possible to reduce PCB costs. I recently did a board that required 4-mil [0.10mm] minimum trace…

People who have had a class on DSP or Signals and Systems are aware that any signal can be broken down into a sum of sinusoids of various amplitudes and frequencies. The Fourier Transform (FT) can break down a signal into its frequency-domain spectral…

Last week while I was debugging a memory bus, my wife came down and asked if I could watch the kids when they woke up. I knew the design was good, so the bus problem was just an assembly defect, which I hoped to find before the baby woke up. She handed…

Most everyone has attended a business conference, gone to a seminar or breakout session there, and discovered that the talk wasn’t what they thought it was about. To avoid offending the speaker, it’s polite to sit through the presentation, avoid checking…

What do you do with the desiccant bags that come with IC shipments? I try to put them in my parts bins to avoid throwing them away. The drawers are not air tight, so I doubt it has any effect, but I hate to throw them away. I don't mind throwing one or…

The modern practice of website password authentication is breaking down. I first began using passwords in the 80s to log on to BBS. I selected a password that was four letters, all lower case. In college, the university VAX required five characters, so…

Should engineers become financiers? Engineers sometimes lament the fact people with engineering and mathematical ability choose to go into finance rather than engineering . Although the finance industry has gotten a bad reputation following the recent…

Engineers as a group are smarter than other people when it comes to applied technical matters. We are bemused by non-technical people using emotionalism and logical fallacies to make important decisions. After years of working in organizations where decisions…

The FCC granted an extension today on the report on the risks of LightSquared's proposed broadband data network interfering with GPS receivers. It is clear that the system would cause some interference. We need to quantify how much and what the design…

I recently finished a board with a sensitive optical detector. The front-end is a trasconductance amplifier detecting currents in the hundreds of femtoamps. The optical detector uses a Peltier cooler that requires around 0.5V at 0.5A. 5V with plenty of…

ESC Chicago Dr. Hugh Herr’s keynote address started off Tuesday at ESC on an optimistic note. His talk was about integration of technology into the human body. He told us the he had both legs amputated at the knee, and he was walking around today on prosthetic…

When I first developed an interested in radio as a hobby, the only multiple access scheme in common use was frequency division. The government would grant an organization, such as a towing company or police department, exclusive rights to use a particular…